Vitamin C cancer fear

High doses of vitamin C could increase the risk of cancer, scientists warn today.

Their findings suggest that the popular 'mega-dose' vitamin C pills may damage cells in the body.

Experts said the study raised real concern about the pills, taken by thousands in the belief that they help ward off colds, protect against heart disease and boost all-round health.

Catherine Collins, chief dietician at St George's Hospital, London, said people who took the pills were acting as 'guinea pigs'.

She said: 'This suggests that there's a potential risk of having more of a nutrient than the body really needs. There's all the vitamin C you need in a single grapefruit, but they are taking ten times the amount and who knows what's going to happen?'

But producers of diet supplements said laboratory experiments did not necessarily reflect what happens in the body.

Britons spend £55million a year on vitamin C pills.The recommended daily intake is between 40 and 60mg, but mega-dose pills can contain up to 1,000mg.

The new study, reported today in the journal Science, could explain why most previous research has failed to confirm the theory that vitamin C supplements offer protection against cancer.

Test-tube experiments at the University of Pennsylvania in Philadelphia suggested that vitamin C can actually trigger a biological process which damages the DNA - or genetic code - in cells. This could create a potential risk of cancer and other diseases such as rheumatoid arthritis.

Dr Ian Blair, who led the research, said: 'It's possible vitamin C isn't working in cancer prevention studies because it's causing as much damage as it's preventing, but that's speculation at this point. What we can say is that vitamin C doesn't work when you expect it to.'

He stressed that his study did not prove high levels of vitamin C could trigger cancer. Dr Blair said: 'Just because you damage DNA doesn't mean you'll get cancer. But if you really wanted to be cautious, you wouldn't use supplements.'

The findings were hotly disputed by the Proprietary Association of Great Britain, which represents manufacturers of medicines and supple-ments. A spokesman said: 'The study must be taken in perspective and should not cause concern.

'It was performed in test tubes and not in the body.'

He said a similar study in Finland had not identified any problem. The spokesman added: 'Vitamin C is an essential antioxidant, which protects the body against potentially-damaging free radicals. It helps fight infection and is essential for wound healing.

'It's also needed for the formation of collagen, for healthy skin and for the formation of other structural materials in bones, teeth and capillaries.'

But Dr Arthur Grollman of the State University of New York, an expert on the causes of cancer, said the implication of the research was serious.

He said: 'Far more caution should be taken over dietary supplements - there should be an insistence on real proof that there's a benefit before taking any.'

Diet experts strongly advised people to stay close to the recommended daily allowance of vitamin C. In the UK, the Government's Committee on Medical Aspects of Nutrition suggests 40mg a day, while the European Commission level is 60mg.

Dr Wendy Doyle, of the British Dietetic Association, said the findings reinforced the message that vitamins should be obtained from natural sources.

She said: 'Fruit and vegetables also contain other plant chemicals that are health-promoting.'